Disposable treatment articles are known in the art and include, for example, disposable absorbent articles, disposable cleaning articles, and disposable delivery articles. Disposable absorbent articles are often used for receiving and storing bodily exudates. Examples of such disposable absorbent articles include diapers, diaper inserts, training pants, adult incontinence articles, and feminine hygiene articles such as sanitary napkins and bandages. Exemplary known disposable cleaning articles include paper towels, disposable non-woven wipes, toilet tissue, facial tissues, hair cleaning wipes, tooth cleaning wipes, and other implements that are adapted to remove contamination or other undesirable materials from a variety of surfaces (e.g., one or more bodily surfaces). Exemplary known disposable delivery articles include facial wipes, moistening wipes, protective hand wipes, cleansing pads, tooth whitening articles, and heat wraps. Disposable delivery articles are typically adapted to deliver one or more beneficial substances or energy such as, for example, a skin care active, lotion or heat, to a variety of surfaces such as one or more bodily surfaces.
Disposable absorbent articles may include a liquid permeable topsheet, a liquid impermeable backsheet and an absorbent core disposed between the topsheet and the backsheet. The absorbent core may be configured to absorb many times its own weight in liquid in order to store lower viscosity bodily exudates such as urine, menses, and/or runny or low viscosity feces. While the absorbent core may absorb the liquid that comes into contact with it, often any solid or highly viscous or particulate-containing material such as, for example, solid or pasty feces received by the absorbent article will typically remain at least partially on the topsheet, and in such instances may come into contact with the skin of a wearer of the absorbent article. It is well known that contact between skin and bodily exudates such as fecal matter may increase the occurrence of undesirable skin rashes or other ailments. BM (i.e., bodily exudate resulting from a bowel movement) or other bodily exudates that adhere or cling to the skin of a wearer will typically have to be cleaned off by the wearer of the absorbent article or a caregiver of the wearer. The removal of BM, for example, from skin may be an undesirable task for both wearers of absorbent articles and caregivers of the wearers. In light of this undesirability, some manufacturers of disposable absorbent articles have sought ways of isolating any BM contained in an absorbent article from the skin of the absorbent article wearer. Additionally, complete removal of feces from the skin is often difficult. Even when the previously soiled skin appears to be visually clean, micro-level contamination may remain on the skin and contribute to increased skin irritation.
One approach to isolating BM includes providing an absorbent article with an opening in the topsheet through which BM can pass to a more isolated portion of the absorbent article such as an interior portion proximate to the absorbent core. Once the BM passes through the opening, the topsheet may be configured to provide a barrier between the BM and the skin of the wearer. In some embodiments, the topsheet may be configured to have a hydrophilic side facing the wearer and a hydrophobic side facing the absorbent core of the article. The topsheet may be configured to have two hydrophobic sides, so that when bodily exudates pass from the wearer side of the topsheet to the absorbent core, they are inhibited or prevented from passing back from the absorbent core to the skin of the wearer. However, this approach may increase the complexity and/or the manufacturing cost a disposable absorbent article and may still leave a portion of the wearer's skin in contact with fecal material.
Another approach to the problem of BM on skin is to provide a barrier composition on the topsheet that repels or at least inhibits BM from sticking to the surface of the skin. For example, certain lotions and skin care compositions are known to at least reduce the tendency of BM to stick to the skin when they are applied to the surface of the skin. Such lotions and skin care compositions are typically hydrophilic or hydrophobic in nature. One drawback associated with the use of hydrophilic lotions on topsheets of absorbent articles is the phenomenon of over-hydration of the portion of skin in contact with the lotion. Over-hydration of the skin may lead to skin irritation and/or a wet skin feeling, and therefore may not provide a suitable option for BM isolation. Hydrophobic lotions, on the other hand, may provide at least some BM isolation and may not contribute significantly to skin over-hydration, but hydrophobic lotions may include other undesirable features such as interfering with the function of the topsheet, having a low washability (e.g., leaving an undesirable residue on the skin of the wearer), having a negative feel or appearance, and/or having insufficient skin cleaning ability. Thus, many manufacturers of absorbent articles desire a means of imparting hydrophobicity to a bodily surface without the negative aspects mentioned above.
Disposable cleaning articles for bodily surfaces may comprise one or more dry or wet-laid layers of a nonwoven material comprising synthetic or natural fibers adapted to remove contamination from skin, hair, or teeth. For example, facial tissues are typically wet-laid cellulosic webs adapted to remove nasal mucous or other waste from the skin, especially in the oral and nasal regions of the body. Toilet tissue is typically a wet-laid cellulosic web adapted to remove fecal material from a user's perianal region. Facial wipes may comprise a synthetic nonwoven web or foam material adapted to remove dirt, makeup, and other contamination from a user's facial region. One approach to increase the efficacy of disposable cleaning articles is to increase the basis weight of the article, which will typically increase the absorptive capacity of the article. While this may be at least partially effective for low viscosity contamination, highly viscous contaminants, visco-elastic contaminants, or contaminants having a high concentration of particulate matter may prove difficult to absorb regardless of the basis weight of the absorbent material. To deal with highly viscous contaminants, some providers of disposable cleaning article may increase the 3-dimensionality of the article, for example, by including depressions ridges, rugosities, and the like in order to provide storage capacity on the article surface for contaminants that are difficult to absorb. However, these approaches still may not be successful for highly adhesive or sticky contaminants, which tend to form a strong bond with a surface. One approach to reduce the adhesive or sticky properties of these kinds of contaminants is to disrupt the bond between the contaminant and the surface to which it is adhered. In some instances, this may be accomplished by using a liquid cleaning agent that includes, for example, water, a lotion, a silicone, and/or a surfactant. However, it may be difficult for the liquid cleaning aid to penetrate to the interface of the contaminant and the surface to which it is joined, and therefore the contaminant may not be removed even with a liquid cleaning aid. Another approach may be to include a beneficial composition that is releasably contained in a disposable cleaning article. For example, a hydrophobic skin care composition may be included in facial tissue and/or toilet tissue in order to reduce the likelihood of undesirable contamination of the skin, when the composition is applied to skin. While a hydrophobic skin care composition may provide the desired benefit of reducing the susceptibility of skin to the irritant effects of contamination, it is still subject to the same drawbacks described above with regard to disposable absorbent articles.
Disposable delivery articles may be adapted to transfer a beneficial substance or effect to the skin of a user and include facial wipes, moistening wipes, protective hand wipes, cleansing pads, tooth whitening articles, and heat wraps. These articles are generally effective at delivering the beneficial substance, but often lack the ability to protect the bodily surface from contaminants that may come into contact with the surface. Providing these articles with the ability to additionally facilitate the removal of undesirable contaminants via the establishment of a highly hydrophobic surface may be highly beneficial.
Existing in nature are surfaces that exhibit an inherent hydrophobicity (e.g., the surface of a lotus leaf). This phenomenon is sometimes referred to as super-hydrophobicity. The inherent hydrophobicity of certain natural surfaces may be due at least partially to hydrophobic nano- and/or micro-structures provided on the surface by one or more naturally occurring hydrophobic materials. In some instances, the material may be produced naturally by an organism of which the surface is a part. In the case of the lotus leaf, the lotus plant produces and exudes a hydrophobic wax onto the surface of its leaves. The hydrophobic wax of the lotus plant has a surface that comprises hydrophobic micro and nano structures, which impart the inherent hydrophobicity to the lotus leaves. The micro and nano structured surface of the lotus leaf comprises a plurality of elevations and depressions wherein the heights of at least some the elevations and the distance between at least some of the elevations are on the order of nanometers, i.e., on a “nanoscale”. When the material that includes the nanostructures is a hydrophobic material such as in the example of the lotus leaf, the relative spacing of the elevations may present a surface that water and other polar liquids are unable to penetrate or adhere to. In addition, when water or other similar liquids come into contact with such naturally hydrophobic surfaces, the water or other liquid may “roll off” of the hydrophobic surface and take any contamination with it. This phenomenon is sometimes referred to as the “Lotus Effect” and may result in a surface that is substantially self-cleaning when exposed to water. Nanostructures have been reproduced on some artificial surfaces through, for example, plasma etching, plasma polymerization, chemical vapor deposition, and surface coupling reactions. However, these methods are typically not suitable for use with certain biological surfaces such as skin.
Descriptions of the lotus effect and/or surfaces comprising nanostructures can be found in US2002/0150724A1 to Nun, et. al.; U.S. Pat. No. 6,660,363B1 to Barthlott; U.S. Pat. No. 5,500,216A to Julian, et. al.; U.S. Pat. No. 6,683,126B2 to Keller, et. al.; US2004/0014865A1 to Keller et. al.; US2003/0096083A1 to Morgan, et. al.; US2003/0124301A1 to Oles, et. al.; US2004/0154106A1 to Oles et. al.; EP1144536B1 to Reihs, et. al.; EP1144537B1 to Reihs, et. al.; EP1144733B1 to Reihs, et. al.; U.S. Pat. No. 6,787,585B2 to Rose, et. al.; US2004/0023824A1 to Zuechner, et. al.; and Biologie in Unserer Zeit, volume 28, Issue No. 5, pages 314-322, Barthlott, et. al.
Accordingly, it would be desirable to provide a disposable treatment article that transfers a composition for creating nanostructures on a bodily surface to the bodily surface during normal use of the article, wherein the nanostructures are capable of preventing, reducing, or resisting the adherence of contamination to the bodily surface. It would also be desirable to provide a nanostructure forming composition on a disposable treatment article that imparts good contamination resistance properties to skin and is not associated with skin over-hydration. It would further be desirable to provide a nanostructure forming composition on a disposable treatment article that renders a biological surface substantially hydrophobic.